Innervation of the vasa nervorum: changes in human diabetics

Area of Science:

• Neuroscience
• Vascular Biology
• Diabetology

Background:

• Nerves rely on intricate networks of unmyelinated axons for innervation.
• The vasa nervorum, blood vessels supplying nerves, are crucial for neural health.
• Diabetes mellitus is associated with peripheral neuropathy, but its vascular underpinnings require further elucidation.

Purpose of the Study:

• To ultrastructurally and immunocytochemically characterize perivascular axons in human sural nerve biopsies.
• To compare the innervation of the vasa nervorum in diabetic and non-diabetic individuals.
• To investigate the relationship between abnormal vasa nervorum innervation and diabetic neuropathy.

Main Methods:

• Human sural nerve biopsies were analyzed using ultrastructural examination.
• Immunocytochemistry was performed using an antibody for protein gene product 9.5 (PGP 9.5), a neuronal marker.
• Vessels were assessed for the presence and state of perivascular axons and Schwann cell units.

Main Results:

• Diabetic patients showed significantly more abnormal innervation of the vasa nervorum compared to non-diabetics.
• Abnormalities included fewer vessels with perivascular axons and more denervated Schwann cell units.
• Remaining axons in diabetics had fewer varicosities, and denervated arterioles displayed structural injury.

Conclusions:

• Perivascular denervation of the vasa nervorum is a prominent feature in diabetic neuropathy.
• Structural defects in denervated arterioles may contribute to endoneurial ischemia and hypoxia.
• Abnormal neural control of blood flow and vascular damage likely play a role in the pathogenesis of diabetic nerve fiber loss.